In commonly assigned copending application Ser. No. 474,070, filed May 28, 1974, now U.S. Pat. No. 3,902,327, for "UNDERWATER ESCAPE APPARATUS", there was described apparatus and procedure for the individual escape of the members of the crew of a submarine in distress at considerable depth, the escape being from a flooding chamber which they enter individually after having donned a suit and a hood. In accordance with that apparatus and procedure, when the depth of immersion is greater than 180 meters, in order to prevent the gaseous embolism each submariner is equipped with a device comprising a parachute for decelerating his velocity in the last part of the ascent to the surface. It is the basic object of the instant invention to provide an improved apparatus for use in such escape procedures, which apparatus overcomes some disadvantages of the apparatus disclosed in this previous application.
In the apparatus of the previous application, automatic opening of the parachute is achieved mechanically due to opening of a container which is fast with the triggering device. It is one of the objects of the instant invention to disassociate, on the one hand, the container containing the parachute and, on the other hand, the device for automatic triggering of opening of the latter, in such manner that it is possible to secure them separately to the submariner's suit, thereby obtaining a less cumbersome apparatus.
The apparatus disclosed in the previous application includes a single spring, the force of which determines simultaneously the depth of immersion at which the device is set and the depth at which the parachute is automatically launched. It is a further object of the instant invention to disassociate the means permitting regulation of the setting depth and the depth of automatic triggering of parachute opening, in such manner that it is possible to regulate these arrangements independently of each other, and such that it is possible to determine the setting depth by means which are more precise than a spring, the characteristics of which may vary in course of time, thereby involving a risk of producing a setting error which might result in death due to embolism.
In general the objects of the present invention are achieved by means of apparatus for use in keeping with the procedures of the previously mentioned earlier application, which apparatus is adapted to be secured to an individual escape suit and comprises, on the one hand, an ascent retarder such as a parachute folded within a container, which may be open, and provided with a pressure responsive member such as a piston, and, on the other hand, a pressure gas cylinder connected to the container by a flexible conduit communicating with the face of the piston opposite the parachute, and equipped with obturating means and means for automatically triggering opening thereof as soon as the immersion depth becomes smaller than a predetermined threshold depth, for example a threshold depth of 60 meters.
Apparatus in accordance with the invention comprises, furthermore, means for setting the automatic opening device of the obturating means only after the immersion depth has exceeded a predetermined limit beyond which there would be a danger of gaseous embolism taking place during the ascent, for example, if the immersion depth has exceeded 180 meters.
Apparatus in accordance with the invention comprises, in a preferred arrangement, obturating means constituted by a cover or cap disposed opposite a striker fast with a piston adapted to slide, under the action of a spring, in a fixed cylinder, which cylinder includes means for locking the piston, the locking means being automatically moved away to free the piston and striker when the immersion depth becomes less than the said predetermined threshold. The locking means preferably comprise balls lodged in orifices recessed through the wall of the fixed cylinder, which balls engage on the one hand in a peripheral groove formed in the piston carrying the striker, and cooperate on the other hand with the wall of a mobile cylinder which is coaxial to the fixed cylinder and surrounds it. The mobile cylinder is fast with a piston which is displaceable in a housing communicating with the exterior of the apparatus via orifices, the piston being maintained in abutment with a diaphragm disposed transversely of the housing by a spring opposing the water pressure thrust, in a position wherein the balls are maintained by the mobile cylinder in the striker locking position.
The resistance of the diaphragm to water pressure is selected to be such that the diaphragm will be ruptured as soon as the immersion depth exceeds the upper limit beyond which the device requires to be set. Rupture of the diaphragm frees the mobile cylinder which, in turn, frees the striker locking balls as soon as the immersion depth becomes smaller than the threshold depth at which the parachute is required to open. Preferably the rupturable diaphragm is engaged at its periphery in the walls of the housing, and is disposed between two rigid plates, for example between two discs, the surface of each disc being slightly smaller than that of the diaphragm, in such manner that the diaphragm is not deformed in flexure before rupturing.
The result achieved by the invention is an improved apparatus for use in keeping with the procedures mentioned in the previously mentioned prior application. The improved apparatus has the advantage that the immersion limit beyond which the device is set (cocked) is obtained with the aid of a diaphragm rupturable under the water pressure, thereby making it possible to determine the threshold with a high degree of precision and a high degree of safety, without risk of modification thereof due to modifications in the properties of a spring in course of time.
A further advantage of apparatus in accordance with the instant invention resides in the fact that the parachute opening threshold is determined by means independent of those determining the setting threshold.
Still a further advantage of apparatus in accordance with the instant invention resides in the fact that the parachute container may be made separate from the device for automatically triggering opening of the parachute, thereby making it possible to fix the parachute container to the bottom of a leg of the escape suit, in such manner that during ascent deceleration the wearer of the suit remains in a vertical position, while at the same time making it possible to secure the pressure gas cylinder and the obturating means at another location on the escape suit where it would be less troublesome, for example, in a lateral "pocket".
There follows a description of a preferred embodiment of the invention, with reference to the accompanying drawings which show, without being limiting, an example of a preferred embodiment of the invention.